What is a stereo matched pair?

I know this may be a silly question, especialy coming from someone like myself whos been recording for a few years now.

I am about to purchase a "stereo matched pair" of mics. They also sell the same mic alone, I want to use these new mics for overheads but also use one of them for vocals and such...I guess my question is - would them being a matched pair stop me from using them independantly.

I'm not totaly farmiliar with this nomanclature although I see all the time.